| 摘要 |
PURPOSE:To make it possible to accumulate high pressure hydraulic fluid n an accumulator by providing a pressure reducing means for lowering hydraulic pressure during the flow rate of hydraulic fluid being high, in a power hydraulic passage in a spool in a control valve which is incorporated in a hydraulic booster and associated with a reaction piston. CONSTITUTION:When a reaction piston 36 which is fitted in a housing 32 together with a power piston 34 is actuated by means if an input rod 42, a control valve 30 associated with the piston 36 through the intermediary of a motion converting mechanism 44 hinders the flow of hydraulic fluid from a pump 16 to a tank 14 so as to increase the pressure of the hydraulic fluid. Further, simultaneously, a power hydraulic fluid passage 126 led to a power pressure chamber 38 is opened to actuate the power piston 34 by means of hydraulic fluid while a part of high pressure hydraulic fluid is fed and accumulated in an accumulator 176 through a pressure accumulating passage 186. In this arrangement, a pressure reducing valve 142 for lowering the pressure of hydraulic fluid during the flow rate of the hydraulic fluid being high is disposed in the power hydraulic fluid passage 128, and the pressure accumulating passage 186 is connected between the pressure reducing valve 142 and a pump. |
